Preheat the oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.

In a mixing bowl, combine flour, sugar, baking powder, and salt.

Add softened butter, milk, eggs, and vanilla extract. Mix until smooth.

Divide the batter evenly between the prepared pans.

Bake for 25-30 minutes or until a toothpick inserted in the center comes out clean.

Let the cakes cool in the pans for 10 minutes, then transfer to wire racks to cool completely.

In a large mixing bowl, beat the cream cheese until smooth.

Add sour cream, sugar, eggs, and vanilla extract. Mix until well combined.

Pour the cheesecake filling over one of the cooled cake layers.

Place the second cake layer on top of the cheesecake filling.

In a small saucepan, combine mixed berries, sugar, and lemon juice.

Cook over medium heat until the berries are soft and the mixture is syrupy, about 5-7 minutes.

Let the berry topping cool slightly before pouring it over the cake.

Pour the berry topping over the assembled cake.

Chill the cake in the refrigerator for at least 2 hours before serving.

Slice and serve chilled.